Converting tar or pitch to coke



May 8, 1934. s. P. MILLER CONVERTING TAR OR PITCH TO COKE Filed Sept; 28, 1929 2 Sheets-Sheet l INVENTOR 5PM ATTORNEY5 May 8, 1934. s. P. MILLER CONVERTING TAR OR PITCH TO COKE Filed Sept. 28, 1929 QSheets-Sheet INVE NTOR 5.7M

ATTORNEY5 UNITED STA Patented May 8, 1934 1,958,217 CONVERTING TAB-OR PITCH T cons Application September 28, 1929, Serial No. 395,867

3 Claims. (CL 202-28) TES PATENT OFFICE This invention relates to the conversion of tar or pitch to coke. This is in part a continuation of my co-pending application Serial No. 384,666 filed August 9, 1929.

5 According to this invention, tar or pitch is converted to coke in a rotating still and during the conversion of the material to coke, hot fuel gases are passed through the still to remove the vapors formed and thus aid in the distillation,

to prevent decomposition of volatile material and thereby to increase the oil yields.

The hot gases employed for flushing the vapors from the still are hot fuel gases, such as hot coke oven gases. Such gases are preferably used at a high temperature at which they still contain their original oil vapor content. The vapors carried by the gases pass through the still and are condensed in the condensers together with oils distilled from the tar or pitch in the no still.

Any type of rotating still which is equipped with heating means may be employed. Agitating or tumbling means, such as bars or rods or balls, etc., may be employed to advantage to tumble 2'2 and agitate the contents of the rotating still and thus aid in the distillation and the production of pitch and prevent the accumulation of pitch or coke on the walls of the still.

The process may be carried out as a batch 99 process, although by continuously passing hot gases through the still and continuously feeding tar or pitch to the still and continuously discharging coke from the still, a continuous operation can be carried on to advantage.

9E5 Where tar-laden gases such as coke oven gases are employed for flushing the vapors from the still, the gases and vapors leaving the still will contain entrained tar or pitch particles. By subjecting the gases to a cleaning operation at to a high temperature, such as by cleaning them in an electrical precipitator or a scrubber, as described in my co-pending application Serial No. 384,666 filed August 9, 1929, clean oils will be produced directly on cooling the cleaned gases. as The scrubber may advantageously comprise a tar still in which tar is sprayed into the hot gases in the form of a line spray, whereby the tar is distilled simultaneously with the scrubbing of the gases and the pitch so produced may be fed to the coking still for conversion to coke therein, as described in my co-pending application Serial No. 384,666 filed August 9,1929.

Various types of heating means may be provided, according to this invention. Electrical heating means may be embedded in the rotating still or a flame such as a gas flame may be brought into direct contact with the exterior wall of the still. The still may also be heated by partial immersion in a heated metal bath, e. g.

a lead bath. According to a preferred arrangement shown in the drawings the still is heated externally by hot combustion gases.

The invention is further described in connection with the accompanying drawings, but it is intended and is to be understood that the invention is not limited thereto.

Fig. 1 is a plan view of the still of this invention in connection with a coke oven plant;

Fig. 2 is an elevation of the still shown in Fig. 1; and

Fig. 3 is a section thru the still.

In the drawings, 1 is a coke oven battery. This battery may be equipped in the usual manner with a collector main 2 and condensers .(not shown), and in addition several ovens of the battery, which may also be connected with the usual collector main thru the usual uptake pipes in the usual way, are connected with the hot gas header 6 thru the uptake pipes '7. By means of the valves 8 in these uptake pipes and the ordinary valves in the usual uptake pipes connected with these same ovens, the gases from these ovens may be sent either to the usual collector main and condensing system or thru the hot gas header 6 into the still 10. The uptake pipes '7, the hot gas header 6 and the exposed portions of the still 10 are advantageously heavily insulated.

The still is a rotating still, driven by a gar 11 which in turn is driven by the motor 12. It is connected with the rest of the apparatus thru the stumng boxes 13 and 14. The gases from the hot gas header enter the still thru the short main 15. The tar or pitch to be converted to coke may be fed to either end of the still. It may pass thru the still in a direction concurrent to or countercurent to the fiowof the gases. According to the drawings it enters the end of the still opposite to that at which the gases enter. The pipe 16 thru which the tar or pitch enters is stationary and is held in place in the pipe 15,

although the end of the pipe 16 projects into the rotating portion of the still and delivers the tar or pitch into this end of the still.

As the tar or pitchpasses through the still it is heated by the hot gases from the furnace 17 and is gradually converted to coke. The vapors produced are swept from the still by"the hot coke oven gases and pass through the main 1% into the condensers 19 and 20. The exhauster 11b 21 draws the gases and vapors through the systern. The gases pass from the exhauster 21 to gas storage'means after recovery of ammonia, etc., but which is not shown. Vapors of low boiling oils liberated from the tar or pitch during the coking operation which are not condensed in the condensers, and also gaseous hydrocarbons produced during the conversion of the tar or pitch to coke are added combustible ingredients present in the coke oven gases entering the still. The resulting mixed gases form a valuable fuel gas.

The furnace 17 is provided with a fuel oil burner or other burner 23 and the hot gases from the burner pass around the baflies 24 and 25 and then up around the still 10 and escape through the stack 26. These waste flue gases may be employed for preheating the tar or pitch.

Loose, tumbling agitators such as balls 27, e. g. of four to six inches in diameter or other tumbling means are advantageously provided in the still to continually tumble or agitate the material as it passes through the still and prevent the pitch or coke from adhering to the walls of the still. The coke produced is in the form of small particles or even powder. It is discharged from the still through the grating 28 in which the openings are of such a size that they will not allow the balls or other agitating or tumbling means employed in the still to pass. The coke is raised to the outlet by the spiral baflles 29 and discharged through the chute 30 and is continuously discharged from the bottom of the chute through the revolving gates 31 into the water in the trough 32 where it is quenched. The conveyor 33 removes the coke from the water and it is collected in the bin 34. Bailles or dams 35' may be provided to prevent the liquid pitch from surging to the coke end of the still and forming wet coke.

Where the operation is carried on as a batch process, a shorter, larger diameter'still may often be employed to advantage. In operating on a continuous basis, the rate at which the tar or pitch is conveyed to the still is so regulated that as the material emerges from the end of the still it has been converted to coke. The time during which the material remains in the still is controlled by the rate at which the material is fed to the still. 7

Where cleaning means is employed for removing entrained impurities from the gases, this cleaning means is situated between the still and the condensers so that the gases are cleaned before they are cooled and on cooling yield clean oils directly. One total oil or several oil frac-' tions may be produced.

Athough the invention has been described more particularly in connection with a process in which hot coke oven gases are passed through the still, it is not limited thereto as other fuel gases such as water gas, gas retort gases, producer gas, etc. may be employed, and they are advantageously used at a temperature approach ing that at which they leave the ovens or retorts, etc. Gases generated during the coking operation are addedto these fuel gases to form a larger volume of fuel gases.

I claim:

1. The continuous method of converting a material of the group consisting of tar and pitch to coke, which comprises adding the material continuously to one end of a rotating still and continuously withdrawing coke from the other end of the still, passing hot fresh coal distillation gases yet containing substantially their original content of tar constituents through the still and into direct contact with the material therein, withdrawing the hot gases and vapors and cooling them to separate therefrom an oil comprising constituents distilled from the tar or pitch, blended with tar constituents originally present in the hot coal distillation gases.

2. The method of converting a material of the group consisting of tar and pitch to coke, which comprises adding the material to a rotating still, passing hot fresh coal distillation gases yet containing substantially their original content of tar constituents through the still and into direct contact with the material therein, subjecting the material in the still to the action of loose, tumbling agitators, withdrawing the hot gases and vapors from the still and cooling them to separate therefrom an oil comprising constituents distilled from the tar or pitch, blended with the tarconstituents originally present in the hot coal distillation gases.

3. The method of converting a material of the group consisting of tar and pitch to coke in a rotating still, such material being naturally fluid at coking temperature, which method comprises continuously introducing the material to one end of the rotating still, passing hot fresh coke oven gases yet containing substantially their original content of tar constituents into the-other end of the still and into direct contact with the material in its naturally fluid condition, simultaneously applying heat externally to the still, rotating the still, and subjecting the contents thereof to the action of loose, tumbling agitators, continuously discharging the coke at that end of the still at which the gases enter, and continuously withdrawing and cooling the gases and vapors'from the still to separate therefrom an oil comprising constituents distilled from the tar or pitch, blended with tar constituents originally present in the hot coke oven gases.

S. P. MILLER. 

